Field of the Invention
The present invention relates to a technique for synchronization processing performed between a server and an information processing apparatus.
Description of the Related Art
Conventionally, as an information processing system including information processing apparatuses, such as an image forming apparatus, there has been known a system in which data under management is synchronized via a network. A system of this type employs a technique in which one information processing apparatus transmits respective contents of changes in data items under its management to another information processing apparatus in an order in which the data items were changed, and the information processing apparatus on the receiving side causes the changes to be reflected on data items under its management in the order of data reception to thereby maintain matching of the order of changes in the data items (see Japanese Patent Laid-Open Publication No. 2011-70636).
Further, there has been known a method in which the matching of the order of changes is maintained by adding date-and-time information of each change to an associated one of the respective contents of the changes, and corresponding data items are processed in the order of date and time. In this method, it is assumed that information processing apparatuses in an information processing system have respective clocks matching each other. In view of this, there has been proposed a technique in which when the clock of one of the information processing apparatuses do not match the clock of another, date-and-time information of data is corrected by correcting the date-and-time information before data exchange (see Japanese Patent Laid-Open Publication No. 2005-117338).
However, in the related art, a case where the same data is changed by a plurality of information processing apparatuses or a case where a clock time of an information processing apparatus is changed is not taken into account. For this reason, when a clock time of an information processing apparatus is changed in a state where the information processing apparatus cannot be connected to a server, it is impossible to properly synchronize setting information or the like between the server and the information processing apparatus, while maintaining the order of time changes. In particular, in the case where the time of the clock is changed a plurality of times in the information processing apparatus in a state where the information processing apparatus cannot be connected to the server, or when the shutdown of the information processing apparatus occurs, there is a fear that synchronization processing cannot be properly performed between the server and the information processing apparatus after the information processing apparatus is connected again to the server. In view of such cases, an arrangement or mechanism is desired which enables proper execution of synchronization processing after the communication with the server is restored.